Weed deflector for an outboard motor water intake

ABSTRACT

A weed deflector for a water intake formed in the lower unit of an outboard motor or stern drive of an inboard outboard engine. The weed deflector includes a fin with a leading edge disposed between a fin base and a tip. A mounting plate fixes the fin base to the lower unit (or stern drive) up flow of the water intake in either a horizontal or vertical orientation. The cross sectional form of the fin induces turbulence in the water flow adjacent to the water intake thereby reducing the ability of debris from obstructing the water intake.

TECHNICAL FIELD

The present invention relates generally to outboard motors. Morespecifically the present invention relates to weed deflectors thateliminate or at least reduce the amount of weeds and debris that canobstruct an outboard motor's water intake(s).

BACKGROUND ART

There exist a number of guards for outboard motors and the lower unitsof inboard/outboard engines that disclose a variety of means to keep itsspinning propeller(s) from coming in contact with objects in the water(like swimmers or debris), and even sub-aquatic features (like rocks andshoals). Typically a wire basket arrangement fixed to the lower portionof the motor enshrouds the propeller. A good example of such a guard isdisclosed in U.S. Pat. No. 5,928,042 attributed to Quiggins entitledPropeller Guard (hereinafter Quiggins '042). Additional examples areU.S. Pat. No. 5,44,346 attributed to Griffin entitled Driveshaft HousingAttachment (hereinafter Griffin '346); U.S. Pat. No. 4,832,634attributed to Kearns entitled Flow Control Device and Protector DeviceFor An Outboard Motor (hereinafter Kearns '634); U.S. Pat. No. 4,078,516attributed to Balius entitled Propeller Guard (hereinafter Balius '516);U.S. Pat. No. 4,070,984 attributed to Kappas entitled Outboard Motor andWeed Guard Therefore (hereinafter Kappas '984); and U.S. Pat. No.4,013,033 attributed to Porter et al entitled Weed Guard for TrollingMotors (hereinafter Porter '033).

Other propeller guards incorporate a cutter to cleave debris intosmaller portions that are in turn deflected away from the spinningpropeller by a plurality of fingers. A good example of such a guard isdisclosed in U.S. Pat. No. 2,355,842 attributed to Arado entitledCombined Cutter, Distributor and protector for Outboard Motors(hereinafter Arado '842).

Protecting the propeller is also achieved by fitting a striker up flowof the outboard motor's lower unit. When debris or a submergedobstruction comes in contact with the striker, the lower unit istemporarily pivoted up thereby removing the spinning propeller from thedebris or obstruction. Such examples are disclosed in U.S. Pat. No.6,179,673 attributed to Leroux entitled Outboard Motor ProtectionApparatus (hereinafter Leroux '673) and U.S. Pat. No. 5,664,977attributed to Dinkowitz et al entitled Boat Propeller Sled (hereinafterDinkowitz '977); and U.S. Pat. No. 5,178,565 attributed to Jacobsonentitled Lower Unit Guard (hereinafter Jacobson '565). All of thepropeller guards disclosed above do not provide any protection for themotor's water intake(s) from debris.

The typical water intake for an outboard motor is fitted with a screen,strainer or grate to keep waterborne debris from being ingested by themotor's water pump. However, debris can become clogged or lodged in sucha screen or strainer, which in turn reduces the flow of cooling water tothe motor. Reducing the flow of cooling water can reduce the work lifeof or at least increase the wear and tear on the motor.

Aside from screens and strainers, a variety of rods or fins positionedover or in the water inlet have been used to prevent clogging of thestrainer (if fitted) or the inlet itself. The rods or fins arepositioned over (or in the inlet) in such a manner to deflect debrisaway from an inlet as water flows around the rods or fins. Examples ofsuch arrangement are disclosed in U.S. Pat. No. 3,147,733 attributed toEngel for an Inlet Screen (hereinafter Engel '733); U.S. Pat. No.3,446,177 attributed to Thornburg et al for a Water Jet PropulsionApparatus (hereinafter Thornburg '177); U.S. Pat. No. 5,468,165attributed to Weber et al for Grass and Debris Exclusion Plate forMarine Jet Pumps (hereinafter Weber '165); and U.S. Pat. No. 5,577,941attributed to Chartier for Marine Jet Drive Weed Grate (hereinafterChartier '941). Each of these devices obstructs the intake not unlikethe debris it attempts to clear. Such obstructing debris deflectorsrequire a larger inlet opening for new construction. Such obstructingdebris deflectors fitted on existing water inlets restrict water flowcausing reduced cooling and increased motor wear. Furthermore, suchobstructing deflectors require a custom fit into or over the inlet inorder to work properly.

In view of the above described deficiencies and issues associated withexisting deflectors, the present invention has been developed toalleviate these drawbacks and provide further benefits to the user.These enhancements and benefits are described in greater detail hereinbelow with respect to several alternative embodiments of the presentinvention.

SUMMARY OF INVENTION

The present invention in its several disclosed embodiments alleviatesthe drawbacks and deficiencies described above with respect toconventional water intake debris deflectors. The present inventionincorporates several additionally beneficial features.

The improved water intake debris deflector includes a fin positioned upflow to a water intake located in the lower unit of an outboard motor(or inboard outboard stern drive). The leading edge of the fin is angledin such a manner as to push debris down and away from a water inlet.Furthermore, the fin's length and thickness causes small amounts ofturbulence in the water flow adjacent to a water intake and propeller.Disrupting the laminar flow of the water adjacent to the water intakereduces the ability of debris to become trapped over the water inlet.Furthermore, disrupting the laminar flow of the water adjacent to apropeller decreases the likelihood of propeller cavitation.

The improved debris deflector may further include a limiting bracketthat prevents excessive fin waiver. Excessive fin waiver can cause themisdirection of water away from an inlet, cavitation bubbles (in extremecases) or even fin failure.

It is the general object of the present weed deflecting invention toprovide a low maintenance passive weed deflector for water inlets formedin lower units of outboard motors or inboard outboard stern drives.

It is another object of the present invention to provide aweed-deflecting device capable of being easily fitted to existing lowerunits of outboard motors or inboard outboard stern drives.

It is a further object of the present invention to provide aweed-deflecting device capable of disrupting the laminar flow of waterin the region of a water intake to reduce debris obstruction.

It is still another object of the present invention to provide aweed-deflecting device capable of disrupting the laminar flow of waterin the region of a propeller to reduce cavitation.

It is yet another object of the present invention to provide a weeddeflecting device which does not obstruct or occlude a water intakeopening formed in the lower unit of an outboard motor or inboardoutboard stern drive.

BRIEF DESCRIPTIONS OF THE DRAWINGS

The invention is described in greater detail in the following examplesand with reference to the attached drawings, in which:

FIG. 1 is an elevation view of an improved weed deflector fixedvertically to an outboard motor's lower unit.

FIG. 2 is a perspective view of an improved weed deflector fixedvertically to an outboard motor's lower unit.

FIG. 3 is an elevation view of an improved weed deflector fixedhorizontally to a stern drive of an inboard outboard engine.

DETAILED DESCRIPTION OF THE INVENTION General Overview

As required, detailed embodiments of the present invention are disclosedherein; however, it is to be understood that the disclosed embodiments aremerely exemplary of the invention that may be embodied in various andalternative forms. The figures are not necessarily to scale, somefeatures may be exaggerated or minimized to show details of particularcomponents. Therefore, specific structural and function detailsdisclosed herein are not be interpreted as limiting, but merely as abasis for the claims and as a representative basis for teaching oneskilled in the art to variously employ in the present invention.

The present invention is directed toward a weed deflector 10 thatincludes at least one fin 11 with a leading edge 15 disposed between afin base 13 and a tip 17. A mounting plate 20 is configured to fix finbase 13 to a lower unit 01 of an outboard motor (or stern drive of aninboard outboard engine 01) (See FIGS. 1 and 3). In a preferredembodiment, fin 11 is fixed in a vertical orientation to a cavitationplate 05 by a mounting plate 20 (See FIG. 1). In another preferredembodiment, a fin 11 is fixed horizontally to a stern drive 01 by amounting plate 20 (See FIG. 3). In either orientation, at least aportion of leading edge 15 extends across a portion of the water flowthat moves adjacent to at least a portion of water inlet 07 (See FIGS. 1and 3).

In a preferred embodiment, the width of fin 11 tapers from base 13 totip 17. Such tapering provides the necessary cant or sweep to theleading edge 15 to direct debris away from water inlet 07 and towardstip 17. It is contemplated that the width of fin base 13 may extendbeyond mounting base plate 15 (See FIG. 2). In an alternativeembodiment, the width of fin base 13 is equal to or less than the widthof mounting base plate 15 (not shown). Tip 17 can be terminated at anydistance from base 13. With a fin 11 in a vertical orientation, thepreferred location of tip 17 is just above skeg 09 (See FIG. 1). With afin 11 in a horizontal orientation, the preferred location of tip 17 isno further than the tips of the propeller 03 (not shown). Such apreferred configurations allows debris to be push away from propeller03. Tip 17 can be pointed, curved or truncated.

In another embodiment, leading edge 15 bows out in a curved fashionbetween fin base 13 and tip 17 (not shown). In such a configuration,leading edge 15 directs debris suspended in a water flow away from thewater inlet 07. While a majority of the debris will be directed towardsa tip 17, some debris can be pushed up toward base 13.

It is contemplated that fin 11 and mounting base plate 15 areconstructed from metals, composite materials and/or a combination ofboth with sufficient characteristics to be wear resistant, withstanddebris strikes and oscillations without significant fatigue. It has beendetermined that a fin 11 with a length between about 2 inches to about24 inches from base 13 to tip 17 with a cross sectional thicknessbetween about 0.001 inches to about 3 inches and a leading edge cantbetween about 1 degree and about 80 degrees off a longitudinal axisrunning the length of a fin 11 causes debris to be deflected from anadjacent water inlet 07; and further encourages water turbulence aroundan adjacent water intake and propeller. The cross sectional shape of fin11 can be elliptical, oval, circular, arcuate, square, polygonal,rectangular and/or a combination thereof.

In one embodiment, fin 11 is constructed from stainless steel (oraluminum) plate with a thickness of about one sixteenth of an inch; abase 13 to tip 17 length of approximately nine to twelve inches and aleading edge cant of about 78 degrees off a longitudinal axis. Such afin 11 is welded to mounting base plate 13. Once mounted in a verticalorientation to a cavitation plate 05, fin 11 directs water borne debrisdown along leading edge 15 and away from water inlet 07. Furthermore arectangular cross section of fin 11 creates turbulence within the waterthat flows adjacent to a water inlet 07 and propeller 03. Suchfin-induced turbulence prevents or at least reduces the likelihood ofwaterborne debris from clogging a water inlet 07. Another benefit ofsuch fin-induced turbulence is the reduction of propeller 03 cavitationduring take-offs.

In a preferred embodiment, fin 11 as described above is fitted with aset of limiting brackets 19 near tip 17. Limiting brackets 19 extendaway from fin 11 and toward outboard motor lower unit 01 (See FIG. 2).If fin 11 begins to oscillate (side to side and/or twist) within a flowof water, limiting brackets 19 come in contact with outboard motor lowerunit 01 to restrain the movement. Limiting brackets 19 prevent excessivefin oscillations. Excessive fin oscillations can cause the misdirectionof water away from an inlet, the creation of cavitation bubbles (inextreme cases) or even fin failure. In another embodiment, limitingbrackets 19 are mounted to outboard motor lower unit 01 (rather than fin11) and extend toward fin 11 (Not shown). If fin 11 begins to oscillate(as described above), limiting brackets 19 come in contact with fin 11to prevent further movement.

In a preferred horizontal orientation of the deflector, a number of fins11, are positioned horizontally across water inlet 07 (See FIG. 3). Thelength of a fin between base 13 and tip 17 is about 2 inches with aleading edge 15 cant of about 70 degrees and an arcuate cross sectionalshape with a thickness of about ¼ of an inch to promote turbulencearound water inlet 07. It is further contemplated that tip 17 isrounded.

A weed deflector 10 and its components have been described herein. Theseand other variations, which will be appreciated by those skilled in theart, are within the intended scope of this invention as claimed below.As previously stated, detailed embodiments of the present invention aredisclosed herein; however, it is to be understood that the disclosedembodiments are merely exemplary of the invention that may be embodiedin various forms.

1. A debris deflector for a water intake for a lower unit of an outboard motor comprising: a fin with a leading edge disposed between a base and a tip, said base fixed to a mounting plate adapted to mount said fin to the lower unit and position a portion of said leading edge up flow of and generally at the same depth as the water intake; said leading edge sweep no less than about 1 degree and no greater than about 80 degrees from a longitudinal axis to re-direct the movement of debris suspended in a water flow toward said tip and away from the water intake; said fin having a length between said base and said tip of no less than about 2 inches and no greater than about 24 inches and a cross sectional thickness no less than about 0.001 inches and no greater than about 3 inches to promote turbulent water flow near the water intake.
 2. A debris deflector as claimed in claim 1, wherein said fin is fixed in a vertical orientation with said tip below said base, said length is no less than about 9 inches and no greater than about 12 inches, said cross sectional thickness is about {fraction (1/16)}^(th) of an inch and said leading edge sweep is about 78 degrees.
 3. A debris deflector as claimed in claim 1, wherein said cross sectional form and thickness is sufficient to cause turbulent water flow near a propeller attached to the lower unit, thereby reducing propeller cavitation.
 4. A debris deflector as claimed in claim 1, wherein a pair of opposing limiting brackets are fixed to said fin near said tip and extend towards the lower unit, said limiting brackets configured to prevent over oscillation of said fin in a water flow.
 5. A debris deflector as claimed in claim 1, wherein a pair of opposing limiting brackets are fixed to the lower unit and extend towards said fin near said tip, said limiting brackets configured to prevent over oscillation of said fin in a water flow.
 6. A debris deflector for a water intake for a lower unit of an outboard motor comprising: a fin with a leading edge disposed between a base and a tip, said base fixed to a mounting plate adapted to mount said fin to the lower unit and position a portion of said leading edge up flow of and generally at the same depth as the water intake; said leading edge sweep no less than about 1 degree and no greater than about 80 degrees from a longitudinal axis to re-direct the movement of debris suspended in a water flow toward said tip and away from the water intake; said fin having a length between said base and said tip of no less than about 2 inches and no greater than about 24 inches and a cross sectional thickness no less than about 0.001 inches and no greater than about 3 inches to promote turbulent water flow near the water intake; said cross sectional form and thickness sufficient to cause turbulent water flow near a propeller attached to the lower unit, thereby reducing propeller cavitation; and said fin has a triangular shape, and said tip is truncated.
 7. A debris deflector as claimed in claim 6, wherein said fin has a vertical orientation, said length is no less than about 9 inches and no greater than about 12 inches, said cross sectional form is rectangular, said cross sectional thickness is about {fraction (1/16)}^(th) of an inch and said leading edge sweep is about 78 degrees.
 8. A debris deflector as claimed in claim 7, wherein said fin is constructed from stainless steel plate.
 9. A debris deflector as claimed in claim 6, wherein said fin has a horizontal orientation, said length is about 2 inches, said cross sectional form is arcuate, said cross thickness is about ¼ of an inch, and said leading edge sweep is about 70 degrees.
 10. A debris deflector as claimed in claim 9, wherein said fin is constructed from aluminum materials.
 11. A debris deflector for a water intake for a lower unit of an outboard motor comprising: a fin with a leading edge disposed between a base and a tip, said base fixed to a mounting plate adapted to mount said fin to the lower unit and position a portion of said leading edge up flow of and at the same depth as the water intake; said leading edge bowed outwardly to re-direct movement of debris suspended in a water flow away from the water intake; said fin having a length between said base and said tip of no less than about 2 inches and no greater than about 24 inches and a cross sectional thickness no less than about 0.001 inches and no greater than about 3 inches to promote turbulent water flow near the water intake. 